HT1635C/HT1635D
44×8 LED Driver
Features
General Description
• Operating voltage: 2.4V~5.5V
The HT1635C/HT1635D series is a memory mapping
LED display controller/driver. The maximum display
capacity of the device is 352 patterns composed of
44 rows and 8 commons. The devices can generate
16 LED illumination levels using software controlled
PWM circuitry. A serial interface is provided to allow
the device to receive instructions for its command
mode and data mode. Only two or four lines are
required to interface the device to a host controller.
The display capacity can be easily extended by
cascading the devices thus expanding its application
possibilities. The device is compatible with most
microcontrollers offering easy interfacing via its two
serial interfaces, an I2C bus or a 4-wire serial bus.
• LED display -- 44 row and 8 Columns
• 88×4 bit RAM display data storage
• 16-level PWM brightness control
• Integrated 256kHz RC oscillator
• I2C-bus or 4-wire serial interface
• Data mode & command mode instructions
• Cascade function for extend applications
• Selectable NMOS open drain output driver and
PMOS open drain output driver for COM lines
• 64-pin LQFP package
Applications
• Industrial control displays
• Digital clocks, thermometers, counters, electronic
meters
• Instrumentation readouts
• Other consumer applications
• LED displays
Selection Table
Most features are common to these devices and the main feature distinguishing them is communication
interface. In real applications, the recommended operating voltage ranges from 4.5V to 5.5V. The following table
summarises the main features of each device.
Part No
HT1635C
VDD
Max. Resolution
Row×Common
Row Source
Current (Min.)
Row Sink
Current (Min.)
Com Source
Current (Min.)
4.5V~5.5V
44x8
50mA
10mA
45mA
HT1635D
Part No
HT1635C
Com Sink Current
(Min.)
PWM Gray Scale
250mA
16-Level for Global
HT1635D
Rev. 1.00
Interface
4-Wire
Package
64LQFP
IC
2
1
July 09, 2021
HT1635C/HT1635D
Block Diagram
Display RAM
CSB/A0
2
RDB/A1
Control &
Timing Circuit
WRB/SCL
VDD
ROW0
DATA/SDA
ROW43
LED
Driver
COM7
COM0
IFS
2
VDD
VSS
OSC
Timing
Generator
SYNC
VSS
PWM Control
Pin Assignment
ROW28
ROW27
ROW26
ROW25
ROW24
ROW23
ROW22
ROW21
ROW20
ROW19
ROW18
ROW17
ROW16
ROW15
ROW14
ROW13
ROW12
ROW11
ROW10
ROW9
ROW8
VDD
ROW7
ROW6
ROW5
ROW4
ROW3
ROW2
ROW1
ROW0
VSS
OSC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
48
47
46
45
44
43
42
HT1635C
41
64 LQFP-A
40
39
38
37
36
35
34
33
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
ROW29
ROW30
ROW31
ROW32
ROW33
ROW34
ROW35
VDD
ROW36
ROW37
ROW38
ROW39
ROW40
ROW41
ROW42
ROW43
VSS
COM7
COM6
COM5
COM4
COM3
COM2
COM1
VSS
COM0
VDD
SYNC
CSB
RDB
WRB
DATA
Rev. 1.00
2
July 09, 2021
HT1635C/HT1635D
ROW28
ROW27
ROW26
ROW25
ROW24
ROW23
ROW22
ROW21
ROW20
ROW19
ROW18
ROW17
ROW16
ROW15
ROW14
ROW13
ROW12
ROW11
ROW10
ROW9
ROW8
VDD
ROW7
ROW6
ROW5
ROW4
ROW3
ROW2
ROW1
ROW0
VSS
OSC
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49
48
47
46
45
44
43
42
HT1635D
41
64 LQFP-A
40
39
38
37
36
35
34
33
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
ROW29
ROW30
ROW31
ROW32
ROW33
ROW34
ROW35
VDD
ROW36
ROW37
ROW38
ROW39
ROW40
ROW41
ROW42
ROW43
VSS
COM7
COM6
COM5
COM4
COM3
COM2
COM1
VSS
COM0
VDD
SYNC
A0
A1
SCL
SDA
Pin Description
Pin Name
I/O
Function
COM0~COM7
O
LED common output lines.
ROW0~ROW43
O
LED row output lines.
VDD
—
Positive power supply.
In PCB Layout that must connect all of the VDD pins to the power plane.
VSS
—
Negative power supply.
In PCB Layout that must connect all of the VSS pins to the GND plane.
DATA/SDA
I/O
Serial data input/output pin. Data is input to / comes out from the shift register at rising
edge of the clock.
• I2C interface serial data (SDA) Input/Output. NMOS open-drain output
• 4-wire serial interface serial data input/output. Input has pull-high resistor and output is
CMOS type.
WRB/SCL
I
Serial clock input pin.
• I2C interface serial clock SCL input.
• 4-wire serial interface WRITE Clock (CLK) input. Connected to pull-high resistor. Data
on the DATA line is latched into the device on the rising edge of the WRB signal.
I
• I2C interface device address data input pin.
• 4-wire serial interface READ clock input. Connected to pull-high resistor. The device
RAM data is clocked out on the falling edge of RDB. The clocked out data will appear
on the DATA line. The host controller can use the next rising edge to latch the clocked
out data.
I
• I2C interface device address data input pin.
• Chip select input. Connected to pull-high resistor. When CSB is high, a data and
command instruction read from or written to the device is disabled and the serial
interface circuit is also reset. If CSB is low data and command instruction transmission
between the host controller and the device is enabled.
I/O
• If the RC MASTER MODE command is programmed, the system clock is sourced from
the internal RC oscillator and the system clock is output on the OSC pin.
• If the SLAVE MODE or EXT CLK MASTER MODE command is programmed, the
system clock is sourced from an external clock on the OSC pin.
I/O
• If the RC MASTER MODE or EXT CLK MASTER MODE command is programmed, the
synchronous signal is output on the SYNC pin.
• If the SLAVE MODE command is programmed, the synchronous signal is input on the
SYNC pin.
RDB/A1
CSB/A0
OSC
SYNC
Rev. 1.00
3
July 09, 2021
HT1635C/HT1635D
Absolute Maximum Ratings
Power Dissipation (PD)(@Ta=25˚C)....................2.5W
Supply Voltage........................... VSS-0.3V to VSS+6.0V
(@Ta=85˚C)....................1.0W
Max junction Temperature (Tj)........................... 125˚C
Input Voltage............................. VSS-0.3V to VDD+0.3V
Storage Temperature............................. -50˚C to 125˚C
Thermal Resistance (Rth).................................40˚C/W
Operating Temperature........................... -40˚C to 85˚C
Note: 1. These are stress ratings only. Stresses exceeding the range specified under “Absolute Maximum Ratings”
may cause substantial damage to the device. Functional operation of this device at other conditions
beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may
affect device reliability.
2. For the actual usage, please refer to the PD-Ta characteristics diagram in the package specification, follow
the power supply voltage, load and ambient temperature conditions to ensure that there is enough margin
and the thermal design does not exceed the allowable value.
D.C. Characteristics
Symbol
Parameter
VDD=2.4V~5.5V; Ta=25°C
Test Conditions
Min.
Typ.
Max.
Unit
2.4
5
5.5
V
—
0.3
0.6
mA
5V No load, Power down mode
—
1
2
μA
Input Low Voltage
DATA, WRB, RDB, SDA, SCL,
5V
CSB, OSC, SYNC
0
—
0.3VDD
V
VIH
Input High Voltage
5V
0.7VDD
—
5
V
IOL1
OSC, SYNC, DATA, SDA
Pins Sink Current
5V VOL=0.5V
18
25
—
mA
IOH1
OSC, SYNC, DATA
Pins Source Current
5V VOH=4.5V
-10
-13
—
mA
IOL2
ROW Sink Current
5V VOL=0.5V
10
13
—
mA
IOH2
ROW Source Current
5V VOH=4.5V
-50
-70
—
mA
IOL3
COM Sink Current
5V VOL=0.5V
250
400
—
mA
IOH3
COM Source Current
5V VOH=4.5V
-45
-60
—
mA
RPH
Pull-high Resistor
5V DATA, WRB, RDB, CSB
18
27
40
kΩ
VDD
Conditions
Operating Voltage
—
—
IDD
Operating Current
No load, LED on,
5V
On-chip RC oscillator
ISTB
Standby Current
VIL
VDD
Rev. 1.00
DATA, WRB, RDB, SDA, SCL,
CSB, OSC, SYNC
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July 09, 2021
HT1635C/HT1635D
A.C. Characteristics
I2C Serial Bus
VDD=2.4V~5.5V, Ta=25°C
Symbol
Parameter
Condition
—
VDD=2.4V to 5.5V VDD=3.0V to 5.5V
Unit
Min.
Max.
Min.
Max.
—
100
—
400
kHz
4.7
—
1.3
—
μs
4
—
0.6
—
μs
fSCL
Clock Frequency
tBUF
Bus Free Time
Time in which the bus
must be free before a new
transmission can start
tHD: STA
Start Condition Hold Time
After this period, the first
clock pulse is generated
tLOW
SCL Low Time
—
4.7
—
1.3
—
μs
tHIGH
SCL High Time
—
4
—
0.6
—
μs
4.7
—
0.6
—
μs
ns
Only relevant for repeated
START condition
tSU: STA
Start Condition Setup Time
tHD: DAT
Data Hold Time
—
0
—
0
—
tSU: DAT
Data Setup Time
—
250
—
100
—
ns
tR
SDA and SCL Rise Time
Note
—
1
—
0.3
μs
tF
SDA and SCL Fall Time
Note
—
0.3
—
0.3
μs
tSU: STO
Stop Condition Setup Time
—
4
—
0.6
—
μs
tAA
Output Valid from Clock
—
—
3.5
—
0.9
μs
tSP
Input Filter Time Constant
(SDA and SCL Pins)
—
20
—
20
ns
Noise suppression time
Note: These parameters are periodically sampled but not 100% tested.
SDA
tf
tLOW
tSU:DAT
tr
tHD:STA
tBUF
tSP
SCL
S
tHD:STA
tHD:DAT
tAA
tHIGH
tSU:STA
tSU:STO
Sr
P
S
SDA
OUT
I2C Bus Timing
Rev. 1.00
5
July 09, 2021
HT1635C/HT1635D
4-wire Serial Bus
VDD=2.4V~5.5V; Ta=25°C
Symbol
Parameter
Test Conditions
VDD
Conditions
Min.
Typ.
Max.
Unit
kHz
fsys
System Clock
5V On-chip RC oscillator
230
256
282
fLED
LED Frame Rate
5V 1/8 duty
—
fSYS/2624
—
Hz
fclk1
Serial Data Clock (WRB Pin)
5V Duty cycle 50%
—
—
1
MHz
fclk2
Serial Data Clock (RDB Pin)
5V Duty cycle 50%
tcs
Serial Interface Reset Pulse Width
— CSB
—
—
500
kHz
250
—
—
ns
Write mode
0.5
—
—
Read mode
1
—
—
tclk
WRB, RDB Input Pulse Width
5V
μs
tr, tf
Rise/Fall Time for WRB, RDB Signal
(Figure 1)
—
—
—
50
100
ns
tsu
Setup Time for DATA to WRB Clock Width
(Figure 2)
—
—
50
100
—
ns
th
Hold Time for DATA to WRB Clock Width
(Figure 2)
—
—
100
200
—
ns
tsu1
Setup Time for CSB to WRB, RDB
Clock Width (Figure 3)
—
—
200
300
—
ns
th1
Hold Time for CSB to WRB, RDB
Clock Width (Figure 3)
—
—
100
200
—
ns
tod
Data Output Delay Time (Figure 4)
—
—
—
100
200
ns
tOFF
VDD Off Times (Figure 5)
— VDD drop down to 0V
10
—
—
ms
tSR
VDD Rising Slew Rate (Figure 5)
—
—
0.1
—
0.8
V/ms
tRSTD
Delay Time After Reset (Figure 5)
—
—
1
—
—
ms
Note: 1. If the conditions of the Power on Reset timing are not satisfied during power ON/OFF, the internal Power
on Reset (POR) circuit will not operate normally.
2. During normal operation, if the VDD drops below the minimum voltage as defined in the operating voltage
spec, then the conditions for the Power on Reset timing must also be satisfied. This means that VDD must
drop to 0V and remain there for 20ms (min.) before rising to the normal operating voltage.
3. Data transfers on the I2C-bus or 4-wire serial bus should be avoided for 1 ms following a power-on to allow
the reset sequence to complete
Rev. 1.00
6
July 09, 2021
HT1635C/HT1635D
tf
WRB, RDB
Clock
tr
90%
tCLK
90%
50%
10%
10%
tCLK
50%
50%
Figure 1
Valid Data
Data
tsu
WRB
Clock
th
50%
Figure 2
CSB
50%
tsu1
WRB, RDB
Clock
50%
50%
th1
tCS
50%
50%
First clock
Data
Figure 3
Last clock
50%
tod
RDB
Clock
50%
Figure 4
VDD
tSR
0%
toff
tRSTD
0.9VDD
CSB
50%
Figure 5
Rev. 1.00
7
July 09, 2021
HT1635C/HT1635D
Functional Description
clock, using the SYS DIS command can neither turn
the oscillator off nor execute the power down mode.
The crystal oscillator option can also be used where
an external frequency source is connected to the
OSC pin. In this case, the system will fail to enter the
power down mode, similar to the case for the external
clock source operation. After an initial system power
on, the device will be in the SYS DIS state.
Power-on Reset
After power is applied, the devices will be initialised
by an internal power-on reset circuit. The status of the
internal circuits after initialisation is as follows:
• System Oscillator will be off
• COM0~COM7 outputs status is high impedance.
External Clock Source
• The row CMOS outputs will all be low
OSC
• The LED display will be in an off state
SEL bit
• Dimming is set to 16/16duty
System
Clock
On-Chip RC Oscillator
256kHz
• The Blinking function will be in an off state.
SEL bit
System Oscillator Configuration
Data transfers on the I2C-bus or 4-wire serial bus
should be avoided for 1 ms following a power-on to
allow the reset initialisation operation to complete.
Display Data Address Pointer
The address mechanism for the display RAM is
implemented using the address pointer. This allows
the loading of an individual display data byte, or a
series of display data bytes, into any location of the
display RAM. The sequence commences with the
initialisation of the address pointer by the address
pointer command.
System Oscillator
The system clock is used to generate the time base
clock frequency LED-driving clock. The clock may
be sourced from an on-chip 256kHz RC oscillator or
from an external clock using software setups. After
the SYS DIS command is executed, the system clock
will stop and the LED duty cycle generator will turn
off. This command is however available only for the
on-chip RC oscillator. Once the system clock stops the
LED display will become blank and the time base will
also stop functioning. The LED OFF command is used
to turn the LED duty cycle generator off. After the
LED duty cycle generator switches off by issuing the
LED OFF command, using the SYS DIS command
will reduce the power consumption, allowing it to
operate as a system power down command. However
if the external clock source is chosen as the system
Blinker
The device contains a versatile blinking function. The
whole display can be made to flash at frequencies
selected by the Blink command. The blinking
frequencies are integer multiples of the system
frequency. The ratios between the system oscillator
and the blinking frequencies depend upon the mode in
which the device is operating, as follows:
• Blinking frequency = 2Hz
ROWn
0.25sec
0.25sec
Turn ON
Turn OFF
Blink ON
Blink OFF
Example of Waveform for Blinker
Display Memory – RAM Structure
• The display RAM is a static 88×4-bit RAM which stores the LED data. Logic “1” in the RAM bit-map indicates
an “on” state of the corresponding LED Row. Similarly, a logic 0 indicates the “off” state.
• There is a one-to-one correspondence between the RAM addresses and the Row outputs, and between the
individual bits of a RAM word and the column outputs. The following shows the mapping from the RAM to the
LED pattern:
COM7
COM6
COM5
COM4
COM3
COM2
COM1
COM0
ROW0
01H
00H
ROW1
03H
02H
ROW2
05H
04H
Rev. 1.00
8
July 09, 2021
HT1635C/HT1635D
COM7
COM6
COM5
COM4
COM3
COM2
COM1
COM0
ROW3
07H
ROW4
09H
06H
08H
ROW5
0BH
0AH
ROW6
0DH
0CH
ROW7
0FH
0EH
ROW8
11H
10H
ROW9
13H
12H
ROW10
15H
14H
ROW11
17H
16H
ROW12
19H
18H
ROW13
1BH
1AH
ROW14
1DH
1CH
ROW15
1FH
1EH
ROW16
21H
20H
ROW17
23H
22H
ROW18
25H
24H
ROW19
27H
26H
ROW20
29H
28H
ROW21
2BH
2AH
ROW22
2DH
2CH
ROW23
2FH
2EH
ROW24
31H
30H
ROW25
33H
32H
ROW26
35H
34H
ROW27
37H
36H
ROW28
39H
38H
ROW29
3BH
3AH
ROW30
3DH
3CH
ROW31
3FH
3EH
ROW32
41H
40H
ROW33
43H
42H
ROW34
45H
44H
ROW35
47H
46H
ROW36
49H
48H
ROW37
4BH
4AH
ROW38
4DH
4CH
ROW39
4FH
4EH
ROW40
51H
50H
ROW41
53H
52H
ROW42
55H
54H
ROW43
57H
56H
D3
D2
D1
D0
Addr
Data
D3
D2
D1
D0
Addr
Data
44ROW & 8COM for 88 × 4 Display RAM
Note: 1.The LED display RAM address is specified by the Address Set command. The address will be
automatically incremented by one after the 4-bit data is shifted in.
2. It is recommended to initialize the display RAM data by clearing all RAM data before the LED display
function is activated. If the RAM data is not initialized before enabling the LED display function, it may
result in abnormal LED display effect after executing the LED ON command.
Rev. 1.00
9
July 09, 2021
HT1635C/HT1635D
LED Driver
The devices include a 352 (44×8) pattern LED driver. This can be setup in a 44x8 format where the COM outputs
can be configured as N-MOS open drain outputs or as P-MOS open drain outputs using software setups. This
feature allows the device to be used in multiple LED applications. The LED drive mode waveforms and scanning
is as follows:
1. N-MOS Open Drain for 44×8 Driver Mode
1 Frame = 8*328*tSYS
4*tSYS
ROWn
328*tSYS
ON
8*tSYS
OFF
ON
COM0
OFF
ON
COM1
OFF
ON
COM6
OFF
ON
COM7
OFF
VDD
OSC
SYNC
VSS
VDD
2.0*tSYS
VSS
ROWn
8*tSYS
COM0
4*tSYS
COM7
OSC
SYNC
2.0*tSYS
Note: tSYS=1/fSYS
Rev. 1.00
10
July 09, 2021
HT1635C/HT1635D
2. P-MOS Open Drain for 44×8 Driver Mode
1 Frame = 8*328*tSYS
4*tSYS
ROWn
328*tSYS
ON
8*tSYS
OFF
ON
COM0
OFF
ON
COM1
OFF
ON
COM6
OFF
ON
COM7
OFF
VDD
OSC
SYNC
2.0*tSYS
2.0*tSYS
VSS
VDD
VSS
ROWn
8*tSYS
COM0
4*tSYS
COM7
OSC
SYNC
2.0*tSYS
Note: tSYS=1/fSYS
Rev. 1.00
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July 09, 2021
HT1635C/HT1635D
Digital Dimming
The devices contain versatile dimming functions. The complete display can be dimmed using pulse width
modulation techniques for the ROW driver with the Dimming command. The relationship between the ROW and
COM digital dimming duty times are shown in the accompanying diagram.
On
COM
ROW
(1/16) duty
ROW
(2/16) duty
ROW
(3/16) duty
ROW
(4/16) duty
ROW
(5/16) duty
ROW
(6/16) duty
ROW
(7/16) duty
ROW
(8/16) duty
ROW
(9/16) duty
ROW
(10/16) duty
ROW
(11/16) duty
ROW
(12/16) duty
ROW
(13/16) duty
ROW
(14/16) duty
ROW
(15/16) duty
ROW
(16/16) duty
4*tSYS
1*T
Off
On
Off
On
2*T
Off
On
3*T
Off
On
4*T
Off
On
5*T
Off
On
6*T
Off
On
7*T
Off
On
8*T
Off
On
9*T
Off
On
10*T
Off
On
11*T
Off
On
12*T
Off
On
13*T
Off
On
14*T
15*T
16*T
Off
On
Off
On
Off
Note: T=20×tSYS
tSYS=1/fSYS
Rev. 1.00
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July 09, 2021
HT1635C/HT1635D
4-wire Serial Interface
Interfacing
Only four lines are required to interface to the
HT1635C. The CSB line is used to initialise the serial
interface circuit and to terminate the communication
between the host controller and the device. If the CSB
pin is set high, the data and command issued between
the host controller and the device are first disabled
and then initialised. Before issuing a mode command
or before mode switching, a high level pulse is
required to initialise the device serial interface. The
DATA line is the serial data input/output line. Data to
be read or written or commands to be written have to
be transferred on the DATA line. The RDB line is the
READ clock input. Data in the RAM is clocked out
on the falling edge of the RDB signal and will appear
on the DATA line. It is recommended that the host
controller read in the correct data during the interval
between the rising edge and the next falling edge of
the RDB signal. The WRB line is the WRITE clock
input. The data, address, and command on the DATA
line are all clocked into the device on the rising edge
of the WRB signal.
Command Format
Software setups are used to configure the devices.
There are two mode commands to configure the
device resources and to transfer the LED display
data. The configurations are setup using the command
mode which has a command mode ID of 100. The
command mode consists of a system configuration
command, a system frequency selection command,
an LED configuration command and an operating
command. The data mode includes READ, WRITE,
and READ-MODIFY-WRITE operations.
The accompanying table shows the data and command
mode IDs.
Mode
ID
Read
Operation
Data
110
Write
Data
101
Read-Modify-Write
Data
101
Command
100
Command
The mode command should be issued before any
data or other commands are transferred. If successive
commands have been issued, the command mode
ID, namely 100, can be omitted. While the system is
operating in the non-successive command or the nonsuccessive address data mode, the CSB pin should
be set to “1” and the previous operation mode will
be reset also. Once the CSB pin returns to “0”, a new
operation mode ID should be issued first.
4-Wire Timing Diagram
Read Mode − ID = 110
CSB
WRB
RDB
DATA
1
1
Data Mode
Rev. 1.00
0
A6
A5
A4
A3
A2
A1
Memory Address1 (MA1)
A0
D0
D1
D2
D3
Data (MA1)
1
1
0
A6
A5
A4
A3
Memory Address1 (MA2)
13
A2
A1
A0
D0
D1
D2
D3
Data (MA2)
July 09, 2021
HT1635C/HT1635D
Read Mode − Successive Address Reading
CSB
WRB
RDB
1
DATA
1
0
A6
Data Mode
A5
A4
A3
A2
A1
A0
D0
D1
Memory Address (MA1)
D2
D3
D0
Data (MA1)
D1
D2
D3
D0
D1
D2
D3
D0
Data (MA1+2)
Data (MA1+1)
D1
D2
D3
D0
Data (MA1+3)
D1
D2
D3
D0
D2
D3
Data (MA1+4)
Note: After reaching the display memory location 0X57H the pointer will reset to 0X00H.
Write Mode − ID = 101
CSB
WRB
1
DATA
0
1
A6
A5
Data Mode
A4
A3
A2
A1
A0
D0
D1
Memory Address1 (MA1)
D2
D3
1
0
1
Data (MA1)
A6
A5
A4
A3
A2
A1
A0
D0
D1
Memory Address2 (MA2)
Data (MA2)
Write Mode − Successive Address Writing
CSB
WRB
DATA
1
0
A6
1
A5
A4
A3
A2
A1
A0
D0
D1
Memory Address (MA1)
Data Mode
D2
D3
D0
Data (MA1)
D1
D2
D3
D0
D1
D2
D3
D0
Data (MA1+2)
Data (MA1+1)
D1
D2
D3
D0
Data (MA1+3)
D1
D2
D3
D0
Data (MA1+4)
Note: After reaching the display memory location 0X57H the pointer will reset to 0X00H.
Read-Modify-Write Mode − ID = 101
CSB
WRB
RDB
DATA
1
0
1
A6
Data Mode
A5
A4
A3
A2
A1
A0
D0
Memory Address1 (MA1)
D1
D2
D3
D0
Data (MA1)
D1
D2
D3
1
0
Data (MA1)
1
A6
A5
A4
A3
A2
A1
A0
D0
Memory Address2 (MA2)
D1
D2
D3
D0
Data (MA2)
D1
D2
D3
Data (MA2)
Read-Modify-Write Mode − Successive Address Accessing
CSB
WRB
RDB
DATA
1
0
1
Data Mode
Rev. 1.00
A6
A5
A4
A3
A2
A1
Memory Address (MA)
A0
D0
D1
D2
Data (MA)
D3
D0
D1
D2
Data (MA)
D3
D0
D1
D2
Data (MA+1)
14
D3
D0
D1
D2
Data (MA+1)
D3
D0
D1
D2
Data (MA+2)
D3
D0
D1
D2
Data (MA+2)
D3
D0
D1
D2
Data (MA+3)
D3
D0
D1
D2
D3
Data (MA+3)
July 09, 2021
HT1635C/HT1635D
Command Mode − ID = 100
CSB
~
~
WRB
~
~
1
DATA
0
0
C8
C7
C6
Command
Mode
C5
C4
C3
C2
C1
C0
C8
~
~
C0
C8
C7
C6
C5
Command …
Command1
C4
C3
Command n
C2
C1
~
C0
~
Command or
Data mode
Command or Data or Address
Mode − Data and Command Mode
CSB
WRB
DATA
Command or
Data mode
Address and Data
Address and Data
Command or
Data mode
Command or
Data mode
Address and Data
4-wire Serial Bus Command Summary
Name
ID
Command code
D/C
Function
Def.
Read
110 A6A5A4A3A2A1A0D0D1D2D3
D
Read data from the RAM
Write
101 A6A5A4A3A2A1A0D0D1D2D3
D
Write data to the RAM
Read-Modify-Write
101 A6A5A4A3A2A1A0D0D1D2D3
D
READ and WRITE to the RAM
SYS DIS
100
0000-0000-X
C
Turn off both system oscillator and LED duty
cycle generator
SYS EN
100
0000-0001-X
C
Turn on system oscillator
LED OFF
100
0000-0010-X
C
Turn off LED duty cycle generator
LED ON
100
0000-0011-X
C
Turn on LED duty cycle generator
Blink OFF
100
0000-1000-X
C
Turn off blinking function
Blink_ON_2Hz
100
0000-1001-X
C
Turn on 2Hz blinking function
Blink_ON_1Hz
100
0000-1010-X
C
Turn on 1Hz blinking function
Blink_ON_0.5Hz
100
0000-1011-X
C
Turn on 0.5Hz blinking function
Slave Mode
RC
Master Mode0
RC
Master Mode1
EXT CLK
Master Mode0
EXT CLK
MASTER MODE1
100
100
100
100
100
0001-0XXX-X
C
0001-100X-X
C
0001-101X-X
C
0001-110X-X
C
0001-111X-X
C
Yes
Yes
Yes
•
•
•
•
Slave mode
Clock source from external clock
System clock input is on the OSC pin
Synchronous signal input is on the SYNC
pin
•
•
•
•
•
Master mode
Clock source from on-chip RC oscillator
OSC pin remains low
SYNC pin remains high
Single chip application only
•
•
•
•
Master mode
Clock source from on-chip RC oscillator
System clock output on the OSC pin
Synchronous signal output on the SYNC
pin
•
•
•
•
•
Master mode
Clock source from external clock,
System clock input on the OSC pin
SYNC pin remains high
Single chip application only
•
•
•
•
Master mode
Clock source from external clock
System clock input on the OSC pin
Synchronous signal output on the SYNC
pin
Yes
Note: It is not recommended to change between MASTER and SLAVE mode after system enable (SYS_EN=1).
Rev. 1.00
15
July 09, 2021
HT1635C/HT1635D
Name
COM OPTION
PWM Duty
ID
Command code
D/C
Function
100
0010-aXXX-X
C
Bit “a” : Open drain type selection
a=0: N-MOS
a=1: P-MOS
100
101X-0000-X
C
PWM 1/16 Duty
100
101X-0001-X
C
PWM 2/16 Duty
100
101X-0010-X
C
PWM 3/16 Duty
100
101X-0011-X
C
PWM 4/16 Duty
100
101X-0100-X
C
PWM 5/16 Duty
100
101X-0101-X
C
PWM 6/16 Duty
100
101X-0110-X
C
PWM 7/16 Duty
100
101X-0111-X
C
PWM 8/16 Duty
100
101X-1000-X
C
PWM 9/16 Duty
100
101X-1001-X
C
PWM 10/16 Duty
100
101X-1010-X
C
PWM 11/16 Duty
100
101X-1011-X
C
PWM 12/16 Duty
100
101X-1100-X
C
PWM 13/16 Duty
100
101X-1101-X
C
PWM 14/16 Duty
100
101X-1110-X
C
PWM 15/16 Duty
100
101X-1111-X
C
PWM 16/16 Duty
Def.
a=0
Yes
Note: 1. X: Don’t care
2. A7~A0: RAM addresses
3. D3~D0: RAM data
4. D/C: Data/command mode
5.Def.: Power on reset default
6. All the bold forms, namely 110, 101, and 100, are mode commands. Among these, 100 indicates the command mode ID. If successive commands have been issued, the command mode ID except for the first
command will be omitted. The source of the tone frequency and of the time base clock frequency can be
derived from an on-chip RC oscillator or an external clock. Calculation of the frequency is based on the
system frequency sources as stated above. It is recommended that the host controller should initialise the
device after a power on reset, as if the power on reset fails, this will lead to device malfunction.
Rev. 1.00
16
July 09, 2021
HT1635C/HT1635D
I2C Serial Interface
P
SDA
Sr
The HT1635D includes an I2C serial interface. The
I2C bus is a bidirectional, two-line communication
link between different ICs or modules. The two lines
are a serial data line, SDA, and a serial clock line,
SCL. Both lines are connected to a positive supply via
a pull-up resistor. When the bus is free both lines are
high. The output stages of devices connected to the
bus must have open-drain or open-collector types in
order to implement a wired or function. Data transfer
is initiated only when the bus is not busy.
SCL
S
or
Sr
8
9
1
2
3-8
9
ACK
P
or
Sr
ACK
• A slave receiver which is addressed must generate
an acknowledge, ACK, after the reception of each
byte.
• The device that provides an acknowledge must pull
down the SDA line during the acknowledge clock
pulse so that it remains at a stable low level during
the high period of this clock pulse.
• A master receiver must signal an end of data to the
slave by generating a not-acknowledge, NACK,
bit on the last byte that has been clocked out of the
slave. In this case, the master receiver must leave
the data line high during the 9th pulse so as to not
acknowledge. The master will generate a STOP or
a repeated START condition.
SDA
SCL
Data line stable: Change of
data allowed
Data valid
START And STOP Conditions
• A high to low transition on the SDA line while SCL
is high defines a START condition.
DATA Output
By Transmiter
• A low to high transition on the SDA line while SCL
is high defines a STOP condition.
DATA Output
By Receiver
not acknowledge
acknowledge
• START and STOP conditions are always generated
by the master. The bus is considered to be busy
after the START condition. The bus is considered
to be free again a certain time after the STOP
condition.
SCL From
Master
SDA
2
7
8
9
S
clk pulse for
acknowledgement
Slave Addressing
• The device requires an 8-bit slave address word
following a start condition to enable the chip for a
write operation. The device address words consist
of a mandatory one, zero sequence for the first four
most significant bits. Refer to the diagram showing
the slave Address. This is common to all LED
devices.
SDA
SCL
1
START
condition
• The bus stays busy if a repeated START(Sr) is
generated instead of a STOP condition. The
START(S) and repeated START(Sr) conditions are
functionally identical.
SCL
P
• The slave address byte is the first byte received
following the START condition from the master
device. The first seven bits of the first byte make up
the slave address. The eighth bit defines whether a
read or write operation is to be performed. When
the R/W bit is “1”, then a read operation is selected.
A “0” selects a write operation.
STOP condition
Byte Format
Every byte put on the SDA line must be 8-bits long.
The number of bytes that can be transmitted per
transfer is unrestricted. Each byte has to be followed
by an acknowledge bit. Data is transferred with the
most significant bit (MSB) first.
Rev. 1.00
7
• Each byte of eight bit length is followed by one
acknowledge bit. This acknowledge bit is a low
level placed on the bus by the receiver. The master
generates an extra acknowledge related clock
pulse.
The data on the SDA line must be stable during the
high period of the clock. The high or low state of the
data line can only change when the clock signal on
the SCL line is low as shown in the accompanying
diagram.
START condition
2
Acknowledge
Data Validity
S
1
• The address bits are “1, 1, 0, 1, 0, A1, A0”. When
an address byte is sent, the device compares the
first seven bits after the START condition. If they
match, the device outputs an Acknowledge on the
SDA line.
17
July 09, 2021
HT1635C/HT1635D
Slave Address
MSB
LSB
1
1
0
1
0
A1
A0
R/W
I2C Timing Diagram
Write Operation – Command Byte
Byte write operation requires a START condition, slave address with R/W bit, a command (1st), a register byte
command (2nd) and a STOP condition for the command byte.
Slave Address
S
1
1
0
1
0
A1
A0
0
Command byte
Register byte
BIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
BIT7 BIT6 BIT5 BIT4 BIT3 BIT2 BIT1 BIT0
Write ACK
ACK
1 st
P
ACK
2nd
Write Operation – Write Display RAM Single Data Byte
A display RAM data byte write operation requires a START condition, a slave address with a write control bit, a
valid display data input /output command, Address byte, a Data byte and a STOP condition.
Slave Address
S
1
1
0
1
0
Command byte
A1
A0
0
1
0
0
0
Write ACK
0
Address byte
0
0
0
X
A6
A5
ACK
1st
A4
A3
DATA byte
A2
A1
A0
D0
D1
ACK
2nd
D2
D3
D0
D1
D2
P
D3
ACK
3rd
Write Operation – Page Write Display Data Operation
Following a START condition, the slave address together with the R/W bit is placed on the bus. The addressed
device will then be provided with an address, which is the address pointer where the data is to be written. The data
to be written then follows after which the internal address pointer is incremented to the next address location on
the reception of an acknowledge clock. After reaching the display memory location 0X57H the pointer will reset
to 0X00H
Slave Address
S
1
1
0
1
0
Command byte
A
1
A
0
1
0
0
0
0
0
0
Address byte
0
0
Write
ACK
D
0
D
1
D
2
n data
Data byte
D D D
3
0
1
D
2
D
3
A7 A6 A5 A4 A3 A2 A1 A0
ACK
D
0
(n+1) data
D
1
D
2
Data byte
D D D
3
0
1
(n+2) data
D
2
ACK
D
3
D
0
(n+3) data
D
1
D
2
Data byte
D D D
3
0
1
(n+x) data
ACK
ACK
ACK
D
2
D
3
(n+x+1) data
P
ACK
Note: The relationship between the LED Display Input/ Output Data transfer format and the RAM mapping data
format is shown below.
MSB
SDA Data
D0
LSB
D1
D2
D3
Address n
Rev. 1.00
D0
D1
D2
D3
Address n+1
18
July 09, 2021
HT1635C/HT1635D
Read Operation – Read Display Data Operation
In this mode, the master reads the device data after setting the slave address. Following the R/W bit, which is
zero, and the acknowledge bit, then follows the display data address setting command code (1st). After this is the
address pointer (An) which is written to the address pointer (2nd). Next comes the START condition and slave
address, followed by an R/W bit which is high. The data which was addressed is then transmitted. The address
pointer is only incremented on reception of an acknowledge clock. The device will place the data at address An+1
onto the bus. The master reads and acknowledges the new byte and the address pointer is incremented to “An+2”.
• If the memory location exceeds the limit value of 0X57H, the memory pointer will return to 00H.
• If only a read command is sent to the I2C interface, then dummy data is sent out.
• This cycle for reading consecutive addresses will continue until the master sends a NACK and STOP condition.
• Read display data format
Slave Address
S
1
1
0
1
0
Command byte
A1
A0
1
0
Write
Slave Address
S
1
1
0
1
0
0
0
0
A0
1
D0
Read
D1
D2
D3
D0
n data
Address byte
0
0
0
ACK
X
A6
A5
A4
A3
D2
D3
D0
D1
(n+1) data
D2
D3
D0
(n+2) data
A0
Data byte
D1
D2
D3
D0
D1
(n+3) data
D2
D3
D0
(n+x) data
ACK
ACK
A1
ACK
Data byte
D1
A2
ACK
Data byte
A1
0
ACK
D1
D2
D3
P
(n+x+1) data
NACK
ACK
I2C Bus Command Summary
Display Data Input Command
This command sends data from the MCU to the device memory map.
(MSB)
(LSB)
Bit6 Bit5 Bit4 Bit3 Bit2 Bit1
Bit7
Bit0
Function
Byte
Display Data Input/
output command
1st
1
0
0
0
0
0
0
0
Address pointer
2nd
X
A6
A5
A4
A3
A2
A1
A0
Note
R/W Def
W
Displays data start
address of the memory
map
W
00H
Note:
• Power on status: the address is set to 00H.
• If the programmed command is not defined the function will not be affected.
System Mode Command
This command controls the system oscillator on/off and display on/off.
Function
Byte
(MSB)
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
(LSB)
Bit0
System mode setting
command
1st
1
0
0
0
0
0
1
0
W
System oscillator and
display on/off setting
2nd
X
X
X
X
X
X
P1
P0
W
Note
R/W
Def
00H
Note:
Name
SYS DIS and LED off
SYS EN and LED off
SYS EN and LED on
P1
0
1
1
Bit
P0
X
0
1
System Oscillator
LED Display
Off
On
On
Off
Off
On
• Power on status: Display off and disable the internal system oscillator.
• If the programmed command is not defined, the function will not be affected.
Rev. 1.00
19
July 09, 2021
HT1635C/HT1635D
Blinking Frequency Command
This command defines the blinking frequency of the display modes.
Byte
(MSB)
Bit7
Bit6
Bit5
Bit4
Bit3
Bit2
Bit1
(LSB)
Bit0
Blinking frequency
command
1st
1
0
0
0
0
1
0
0
W
Blinking frequency
setting
2nd
X
X
X
X
X
X
P1
P0
W
Function
Note
R/W
Def
00H
Note:
Bit
P1
0
0
1
1
Blinking Frequency
P0
0
1
0
1
Blinking off
2Hz
1Hz
0.5Hz
• Power on status: Blinking function is switched off.
• If the programmed command is not defined, the function will not be affected.
COM Option Command
Function
(MSB)
(LSB)
Bit6 Bit5 Bit4 Bit3 Bit2 Bit1
Bit7
Bit0
Byte
Note
R/W Def
Driver output of COM
setting command
1st
1
0
0
0
1
0
0
0
W
COM pin option setting
2nd
X
X
X
X
X
X
X
P0
W
00H
Note:
Bit
P0
0
1
COM pin open drain type selection
N-MOS
P-MOS
• Power on status: The COM N-MOS open drain output is setup.
• If the programmed command is not defined the function will not be affected.
Cascade Set Mode Command
This command will select master/slave mode and input clock source.
(MSB)
(LSB)
Bit6 Bit5 Bit4 Bit3 Bit2 Bit1
Bit7
Bit0
Function
Byte
Note
R/W
Cascade set mode command
1st
1
0
1
0
0
0
0
0
W
Master/ slave select and
input clock source setting
2nd
X
X
X
X
X
P2
P1
P0
W
Def
04H
Note:
Name
RC
Master Mode0
RC
Master Mode1
EXT CLK
Master Mode0
EXT CLK
Master Mode1
Slave Mode
P2
Bit
P1
P0
1
0
0
1
0
1
1
1
0
1
1
1
0
X
X
Master/Slave Input Clock
Select
Source
Sync pin
Note
Status
Always
Only single chip
Output Hi-Z
Output high
application
On Chip RC
Master mode
Oscillator
Output
Output
Master mode
External
OSC
Slave mode
External
OSC
OSC pin
Status
Input
Always
Only single chip
Output high
application
Input
Output
Input
Input
• Power on status: The RC MASTER MODE0 is selected.
• It is not recommended to change between MASTER and SLAVE mode after a system enable (SYS_EN=1)
• If the programmed command is not defined the function will not be affected.
Rev. 1.00
20
July 09, 2021
HT1635C/HT1635D
PWM Duty Command
This command controls the row pulse width.
Function
Byte
(MSB)
(LSB)
Bit6 Bit5 Bit4 Bit3 Bit2 Bit1
Bit7
Bit0
Note
R/W Def
PWM setting command
1st
1
1
0
0
0
0
0
0
W
Pulse width of ROW setting
2nd
X
X
X
X
P3
P2
P1
P0
W
0FH
Note:
P3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
P2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
Bit
P1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
P0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
PWM duty
1/16
2/16
3/16
4/16
5/16
6/16
7/16
8/16
9/16
10/16
11/16
12/16
13/16
14/16
15/16
16/16
• Power on status: 16/16 PWM duty is selected.
• If the programmed command is not defined the function will not be affected.
Rev. 1.00
21
July 09, 2021
HT1635C/HT1635D
Application Circuits
LED Matrix Circuit
ROW0
ROW1
ROW2
ROW3
ROW4
ROW5
ROW6
ROW7
ROW37
ROW38
ROW39
ROW40
ROW41
ROW42
ROW43
COM0
COM1
COM6
COM7
LED Display -- 44 ROW × 8 COM
Rev. 1.00
22
July 09, 2021
HT1635C/HT1635D
Communication Bus Type Circuit
The deivce are compatible with most microcontrollers and communicates using two serial interfaces, an I2C bus or
a 4-wire serial bus.
VDD
VDD
VDD
MCU
HT1635C
0.1uF
ROW 0
~
ROW 43
Port A
CSB
Port B
WRB
Port C
RDB
Port D
DATA
COM 0
~
COM 7
OSC
VSS
VSS
4-Wire Serial Bus
VDD
VDD
MCU
VDD
4.7kΩ
4.7kΩ
HT1635D
0.1uF
ROW 0
~
SCL
Port B
SDA
Port C
A0
Port D
A1
ROW 43
COM 0
~
Port A
COM 7
OSC
VSS
VSS
I2C Serial Bus
Rev. 1.00
23
July 09, 2021
HT1635C/HT1635D
Low Power LED Application – Direct Drive
44 ROW × 8 COM Example: N-MOS Open Drain Output
R*44
ROW 0
~
~
4
MCU
ROW 0
ROW 43
ROW 43
HT1635C/HT1635D
LED Matrix
Communication
bus
COM 0
COM 0
~
~
COM 7
COM 7
Note: 1. Values of the R resistors are selected depending on the power consumption of the LEDs.
2. In PCB Layout that must connect all of the VDD pins to the power plane.
3. In PCB Layout that must connect all of the VSS pins to the GND plane.
High Power LED Application – COM with Transistor Buffer
44 ROW × 8 COM Example – P-MOS Open Drain Output and 8 COM Option
R*44
ROW 0
~
4
~
MCU
ROW 0
ROW 43
ROW 43
HT1635C/HT1635D
LED Matrix
Communication
bus
COM 0
~
COM 0
R*8
~
COM 7
COM 7
NPN*8
R*8
Note: 1. Values of the R resistors are selected depending on the power consumption of the LEDs.
2. In PCB Layout that must connect all of the VDD pins to the power plane.
3. In PCB Layout that must connect all of the VSS pins to the GND plane.
Rev. 1.00
24
July 09, 2021
HT1635C/HT1635D
Cascade Function
Low Power LED Application − In the Case, the COM Pins Output Must be Set to N-MOS Open
Drain Outputs
• Example 1: Direct Driving for 4-wire Serial Bus
LED Matrix
LED Matrix
ROW 0
ROW 43
COM 0
COM 7
ROW 0
ROW 43
LED Matrix
COM 0
COM 7
ROW 0
R*44
R*44
ROW 0
ROW 43
COM 0
COM 7
HT1635C
(Master)
VDD
0.1uF
VSS
CSB
WRB RDB
ROW 43
COM 0
SYNC
COM 7
HT1635C
(Slave)
0.1uF
OSC
COM 7
VSS
ROW 0
CSB
WRB
RDB DATA
ROW 43
COM 0
COM 7
HT1635C
(Slave)
0.1uF
VSS
SYNC
COM 0
COM 7
VDD
ROW 0
VDD
OSC
ROW 43
R*44
VDD
ROW 0
VDD
DATA
COM 0
R*44
VDD
VDD
LED Matrix
ROW 43
CSB
WRB RDB DATA
ROW 0
ROW 43
OSC
VSS
SYNC
COM 0
COM 7
OSC
SYNC
HT1635C
(Slave)
VDD
0.1uF
CSB
WRB
RDB DATA
VDD
VDD
0.1uF
MCU
VSS
4-Wire Serial bus
Note: 1. Cascading can also be implemented using software. Users must set the Master in the master mode and the
Slave in the slave mode using the commands. The CSB pin must be connected to the MCU individually
for independent read and write.
2. Values of the R resistors are selected depending on the power consumption of the LEDs.
3. In PCB Layout that must connect all of the VDD pins to the power plane.
4. In PCB Layout that must connect all of the VSS pins to the GND plane.
• Example 2: Direct Driving for I2C Serial Bus
LED Matrix
LED Matrix
ROW 0
ROW 43
COM 0
COM 7
ROW 0
ROW 43
LED Matrix
COM 0
COM 7
ROW 0
R*44
R*44
ROW 0
ROW 43
0.1uF
VSS
COM 0
COM 7
HT1635D
(Master)
VDD
A0
A1
SCL
SDA
ROW 43
SYNC
VSS
COM 0
COM 7
A0
ROW 0
A1
SCL
SDA
ROW 43
VSS
COM 0
COM 7
HT1635D
(Slave)
0.1uF
SYNC
COM 0
COM 7
COM 0
COM 7
OSC
SYNC
R*44
VDD
OSC
ROW 43
VDD
ROW 0
HT1635D
(Slave)
0.1uF
OSC
COM 7
VDD
ROW 0
VDD
VDD
VDD
LED Matrix
COM 0
R*44
VDD
VDD
ROW 43
A0
A1
SCL
SDA
ROW 0
ROW 43
HT1635D
(Slave)
VDD
0.1uF
OSC
SYNC
VDD
VSS
A0
A1
SCL
SDA
VDD VDD
4.7KΩ
4.7KΩ
VDD
0.1uF
VSS
MCU
I2C Serial bus
Note: 1.Cascading can also be implemented using software. Users must set the Master in the master mode and the
Slave in the slave mode using the commands. The CSB pin must be connected to the MCU individually
for independent read and write.
2. Values of the R resistors are selected depending on the power consumption of the LEDs.
3. In PCB Layout that must connect all of the VDD pins to the power plane.
4. In PCB Layout that must connect all of the VSS pins to the GND plane.
Rev. 1.00
25
July 09, 2021
HT1635C/HT1635D
High Power LED Application − In the Case, the COM Pins Output Must be Set to P-MOS Open
Drain Outputs.
• Example 1: COM with Transistor Buffer for 4-wire Serial Bus
LED Matrix
LED Matrix
ROW 0
ROW 43
COM 0
COM 7
ROW 0
LED Matrix
ROW 43
COM 0
NPN*8
COM 7
ROW 0
R*8
COM 0
0.1uF
CSB
VSS
WRB RDB DATA
COM 7
ROW 0
ROW 43
COM 0
COM 7
HT1635C
(Slave)
0.1uF
SYNC
R*8
R*8
R*8
VDD
VDD
OSC
NPN*8
R*44
R*8
HT1635C
(Master)
VSS
CSB
VDD
ROW 0
ROW 43
COM 0
0.1uF
OSC
SYNC
COM 7
HT1635C
(Slave)
VDD
WRB RDB DATA
COM 7
COM 0
R*8
VDD
ROW 43
ROW 43
NPN*8
R*8
VDD
ROW 0
R*44
R*8
ROW 0
COM 8
COM 0
NPN*8
R*43
R*44
VDD
LED Matrix
ROW 43
VSS
CSB
ROW 0
ROW 44
0.1uF
WRB RDB DATA
OSC
SYNC
COM 0
COM 7
OSC
SYNC
HT1635C
(Slave)
VDD
VSS
CSB
WRB RDB DATA
VDD
VDD
0.1uF
MCU
VSS
4-Wire Serial bus
Note: 1. Cascading can also be implemented using software. Users must set the Master in the master mode and the
Slave in the slave mode using the commands. The CSB pin must be connected to the MCU individually
for independent read and write.
2. Values of the R resistors are selected depending on the power consumption of the LEDs.
3. In PCB Layout that must connect all of the VDD pins to the power plane.
4. In PCB Layout that must connect all of the VSS pins to the GND plane.
• Example 2: COM with Transistor Buffer for I2C Serial Bus
LED Matrix
LED Matrix
ROW 0
COM 0
ROW 43
COM 7
ROW 0
LED Matrix
COM 0
ROW 43
COM 7
ROW 0
VSS
COM 0
COM 7
HT1635D
(Master)
A0
A1
SCL
SDA
ROW 0
ROW 43
OSC
SYNC
VSS
COM 0
COM 7
HT1635D
(Slave)
VDD
A0
A1
SCL
SDA
ROW 0
ROW 43
VSS
SYNC
COM 0
COM 7
HT1635D
(Slave)
0.1uF
OSC
R*8
R*8
VDD
VDD
VDD
VDD
NPN*8
VDD
0.1uF
COM 7
R*44
R*8
VDD
ROW 43
COM 0
ROW 43
R*8
R*8
R*8
ROW 0
ROW 0
R*44
R*8
R*8
VDD
COM 7
NPN*8
R*44
VDD
LED Matrix
COM 0
NPN*8
NPN*8
R*44
0.1uF
ROW 43
A0
A1
SCL
SDA
ROW 0
ROW 43
OSC
SYNC
VDD
VSS
COM 0
COM 7
OSC
SYNC
HT1635D
(Slave)
VDD
0.1uF
A0
A1
SCL
SDA
VDD VDD
4.7KΩ
4.7KΩ
VDD
0.1uF
MCU
VSS
I2C Serial bus
Note: 1. Cascading can also be implemented using software. Users must set the Master in the master mode and the
Slave in the slave mode using the commands. The CSB pin must be connected to the MCU individually
for independent read and write.
2. Values of the R resistors are selected depending on the power consumption of the LEDs.
3. In PCB Layout that must connect all of the VDD pins to the power plane.
4. In PCB Layout that must connect all of the VSS pins to the GND plane.
Rev. 1.00
26
July 09, 2021
HT1635C/HT1635D
Cascade Control Flow
Power On
SYS DIS
(Master,Slave)
COM OPTION
(Master,Slave)
MASTER MODE
(Master)
SLAVE MODE
(Slave)
SYS ON
(Master,Slave)
Write RAM Data
(Master,Slave)
LED ON
(Master,Slave)
Update RAM Data
(Master,Slave)
Rev. 1.00
27
July 09, 2021
HT1635C/HT1635D
Package Information
Note that the package information provided here is for consultation purposes only. As this information may be
updated at regular intervals users are reminded to consult the Holtek website for the latest version of the Package/
Carton Information.
Additional supplementary information with regard to packaging is listed below. Click on the relevant section to be
transferred to the relevant website page.
• Further Package Information (include Outline Dimensions, Product Tape and Reel Specifications)
• Packing Meterials Information
• Carton information
Rev. 1.00
28
July 09, 2021
HT1635C/HT1635D
64-pin LQFP (7mm×7mm) Outline Dimensions
Symbol
Min.
Nom.
Max.
A
—
0.354 BSC
—
B
—
0.276 BSC
—
C
—
0.354 BSC
—
D
—
0.276 BSC
—
E
—
0.016 BSC
—
F
0.005
0.007
0.009
G
0.053
0.055
0.057
H
—
—
0.063
I
0.002
—
0.006
J
0.018
0.024
0.030
K
0.004
—
0.008
α
0°
—
7°
Symbol
Rev. 1.00
Dimensions in inch
Dimensions in mm
Min.
Nom.
Max.
A
—
9.00 BSC
—
B
—
7.00 BSC
—
C
—
9.00 BSC
—
D
—
7.00 BSC
—
E
—
0.40 BSC
—
F
0.13
0.18
0.23
G
1.35
1.40
1.45
H
—
—
1.60
I
0.05
—
0.15
J
0.45
0.60
0.75
K
0.09
—
0.20
α
0°
—
7°
29
July 09, 2021
HT1635C/HT1635D
Copyright© 2021 by HOLTEK SEMICONDUCTOR INC.
The information appearing in this Data Sheet is believed to be accurate at the time
of publication. However, Holtek assumes no responsibility arising from the use of
the specifications described. The applications mentioned herein are used solely
for the purpose of illustration and Holtek makes no warranty or representation that
such applications will be suitable without further modification, nor recommends
the use of its products for application that may present a risk to human life due to
malfunction or otherwise. Holtek's products are not authorized for use as critical
components in life support devices or systems. Holtek reserves the right to alter
its products without prior notification. For the most up-to-date information, please
visit our web site at http://www.holtek.com.
Rev. 1.00
30
July 09, 2021
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